Model engine magneto



P 1949- v E. VOLL'ENWEIDER 2,483,305

MODEL ENGINE MAGNETO Filed Jan. 14, 1947 INVENTOR .E'miZ Dalian weia'er ATTORNEYS Patented Sept. 27, 1949 UNITED STATES PATENT OFFICE MODEL ENGINE MAGNETO Emil Vollenweider, Sacramento, Calif.

Application January 14, 1947, Serial No. 721,889

7 Claims.

1 This invention relates to an improved induction type direct drive magneto for model engines, particularly engines having a flywheel, and designed for use in model racing cars or the like.

One object of this invention is to provide, in combination with a model engine which includes a drive shaft extending through a projecting crankcase boss and a flywheel on the shaft beyond the boss; 2. novel magneto mounted in part on the crankcase boss and in part in the flywheel.

Another object of this invention is to provide a combination, as in the preceding paragraph, wherein the armature is of novel construction and supported from the crankcase boss; the induction rotor being included in the flywheel.

A further object of the invention is to provide a model engine magneto, of the type described, wherein the assembly is simple, compact, and yet rugged; being adaptable to standard-make engines.

A further object of the invention is to provide a practical model engine magneto, which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig. 1 is a side elevation of a flywheel type model engine fitted with the magneto.

Fig. 2 is a sectional plan of the assembly on line 2-2 of Fig. 1.

Fig. 3 is an inner end view of the armature and coil unit, detached.

Fig. i is an outer end end view of the same.

Fig. is an inner end view of the flywheel and rotor unit, detached.

Referring now more particularly to the drawings and to the characters of reference marked thereon, the improved model engine magneto is adapted for use in combination with a model or midget engine, indicated generally at l which engine includes a cylinder 2 fitted, at its upper end, with a spark plug 3, and supported and mounted, at its lower end, in connection with a crankcase 4.

The crankcase 4 includes, at one end thereof, a crankcase boss 5 supported by a bracket 6; such boss having a bearing unit therein in supporting relation to the adjacent and projecting end of the engine crankshaft 8.

At its outer end the projecting portion of the engine crankshaft 8 is fitted with a flywheel 9 retained in place by a nut 10 threaded onto said crankshaft.

The magneto comprises an upstanding mounting block I! disposed transversely of the projecting portion of the crankshaft, and is formed with a bore [2, into which the crankshaft boss 5 engages. The mounting block II is split at the bottom, as at 13, and a cross screw [4 is employed to clamp the split mounting block ll onto said boss in selected position.

The mounting block ll supports an armature, indicated generally at l5, which armature includes upstanding, transversely spaced field pieces is disposed on opposite sides of the axis of the flywheel The armature I5 is of laminated steel sheet construction, with the laminations of the field pieces l6 extending in forwardly converging relation from opposite sides of the mounting block H, as clearly shown in Fig. 2; the adjacent corners of said mounting block being chamfered, as at IT, so that the field pieces 56 may be rigidly mounted flush thereagainst, by screws l8. The forward or working faces of the field pieces l6 are cut at right angles to the flywheel axis, whereby said faces are of greater width than the combined thickness of the diagonally disposed armature laminations.

Above the field pieces Hi the laminations continue upwardly as armature legs I9, which are twisted through 45, and are connected, at their upper ends, by a core 20 disposed in spaced relation above the mounting block II.

The core 20 is wound with an induction coil 21 which includes primary and secondary windings; the primary winding including leads 22 and 23, while a high tension lead 24 leads from the secondary of said induction coil to the spark plug 3.

The primary lead 22 is grounded to the core 20, and the primary lead 23 leads to connection with one side of a timing or make-and-break unit 25 mounted on the back side of the block II. The make-and-break unit 25 includes separable points 26 and an actuating finger 21 riding a rotary cam 23 formed on the projecting portion of the crankshaft 8 directly to the rear of the crankcase boss 5. It will thus be seen that upon operation of the engine and rotation of the crankshaft 8, the described cam arrangement recurringly makes and breaks the points 26, whereby to properly time the engine I.

The induction rotor of the magneto is incorporated in the flywheel 9 and comprises the following structural arrangement:

The flywheel 9 is of brass or other non ma,g-

netic material, and is formed, from its inner face, with a concentric, annular channel surrounding a hub 30.

A pair of permanent magnets 3| of substantially half circle extent are disposed in the channel 29 on opposite sides of th hub 30, as shown. Between the permanent magnets 3| and the field pieces l6 of the armature IS, the flywheel is fitted, within the channel 29, with opposed arcuate soft iron pole shoes 32 which lap the permanent magnets 3|. Retaining screws 33 extend from the pole shoes 32 through relieved end portions of the magnets 3|, and thence are threaded into the flywheel 9, whereby to maintain the assembly of said shoes and magnets fixed in the channel 29.

The pole shoes 32 and magnets 35 are magnetically insulated from the crankshaft 8 by reason of the fact that th flywheel 9 is of a nonmagnetic material.

Operation When the engine I is in operation, with the flywheel 9 and included induction rotor turning, the movement of the pole shoes 32 past the field pieces I6 in relatively close but clearance relation, induces a current in the coil 2|, which current on the high tension side is delivered by the lead 24 to the sparkplug 3.

With the described magneto, it may be incorporated in a flywheel type midget or model engine between the flywheel and crankcase, whereby the entire assembly is compact, yet relatively simple in its structure, providing practical timed ignition means for the engine. The arrangement is such that it is sturdy and requires a minimum of adjustment; there being few wearing parts, and consequently little necessity of replacement thereof.

From the foregoing description it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired:

1. A magneto for a model engine having a crankcase, a projecting crankshaft, and a flywheel on the latter, the magneto including an armature, means adapted to mount the armature in connection with the crankcase in surrounding relation to the projecting crankshaft adjacent the flywheel, and means adapted to form an induction rotor on the flywheel in cooperative relation to the armature; said armature including laminated sheet metal field pieces on opposite sides of the magneto axis, the laminations of said field pieces converging forwardly relative to said axis, and the working faces of said field pieces being formed at substantial right angles to such axis.

2. A magneto for a model engine having a crankcase, a projecting crankshaft, and a flywheel on the latter, the magneto including an armature, means adapted to mount the armature in connection with the crankcase in surrounding relation to the projecting crankshaft adjacent the flywheel, and means adapted to form an induction rotor on the flywheel in cooperative relation tothe armature; the armature mounting mean being a block extending transversely of the magneto axis,

and said armature including laminated sheet metal field pieces mounted on the block on opposite sides of said axis, the laminations of said field pieces converging forwardly relative to said axis, and the working faces of said field pieces being formed at substantial right angles to such axis.

3. A magneto, as in claim 2, in which adjacent edges of the mounting block are chamfered to matchingly engage said converging field pieces and means securing the field pieces to said corners.

4. A magneto for a model engine having a crankcase, a projecting crankshaft, and a flywheel on the latter, the magneto including an armature, means adapted to mount the armature in connection with the crankcase in surrounding relation to the projecting crankshaft adjacent the fiywheel, and means adapted to form an induction rotor on the flywheel in cooperative relation to the armature; the flywheel having an annular channel therein concentric to the magneto axis and opening toward the armature, a pair of substantially semi-circular permanent magnets disposed in the channel in opposed, adjacent end to end relation, and a pair of opposed arcuate pole shoes in the channel overlying the permanent magnets, on the outside, in lapping relation to adjacent end portions thereof, and securing elements extending from the pole shoes into the bottom of the channel so as to maintain the assembly of said magnets and shoes in said channel.

5. In the combination of a model engine having a crankcase, a projecting crankshaft, and a flywheel on the projecting crankshaft; a magneto including an armature, means supporting the armature from the crankcase between the latter and the flywheel, and means forming an induction rotor in the flywheel in cooperative relation to the armature; the armature including field pieces on opposite sides of the magneto axis converging toward the rotor.

6. In the combination of a model engine having a crankcase, a. projecting crankshaft, and a flywheel on the projecting crankshaft; a magneto including an armature, means supporting the armature from the crankcase between the latter and the flywheel, and means forming an induction rotor in the flywheel in cooperative relation to the armature; the armature including field pieces on opposite sides of the magneto axis, and the rotor including a permanent magnet and opposed pole shoes mounted to run in adjacent, cooperative relation to the field pieces, the laminations of said field pieces converging forwardly relative to said axis, and the working faces of said field pieces being formed at substantially right angles to such axis.

7. In the combination of a model engine having a crankcase, a projecting crankshaft, and a flywheel on the projecting crankshaft; a magneto including an armature, the crankcase having a boss surrounding the projecting crankshaft, a mounting block secured on the boss, means attaching the armature to the block between the crankcase and flywheel, the armature including field pieces on opposite sides of the magneto axis, and means forming an induction rotor in the flywheel in cooperative relation to the armature; the armature including spaced legs extending from the field pieces, a core connecting the legs at the free end, and an induction coil about the core; the field piecesbeing of laminated construction and converging in the direction of the rotor, the working faces of the field pieces being at sub- 5 stantially right angles to the magneto axis whereby said faces are wider than the thickness of the corresponding laminated field pieces.

EMIL VOLLENWEIDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 21,679 Jacobi Dec. 31, 1940 778,707 Reichenbach Dec. 27, 1904 809,268 Le Pontois Jan. 2, 1906 914,532 Thordarson Mar. 9, 1909 Number Number Name Date Mueller Mar. 23, 1915 Butterfield Mar. 7, 1916 Wacker May 1, 1917 Oglesby Apr. 6, 1918 Oglesby Aug. 13, 1918 Van Deventer Oct. 29, 1918 Swartz Feb. 4, 1919 Nowosielski Apr. 13, 1937 Vollenweider Oct. 7, 1941 FOREIGN PATENTS Country Date Germany Mar. 21, 1924 

